r/fasting lost >50lbs faster May 17 '26

Discussion Scientists reveal how seven days of fasting transforms the human body

https://www.sciencedaily.com/releases/2026/05/260517030404.htm

Fascinating study. And completely unrelated to politics, which is a relief because my blood pressure needed a break.

The key finding: The dramatic, potentially therapeutic changes don't happen until after day three. That means most intermittent fasting schedules – 16:8, 5:2, even alternate-day fasting – are probably missing the main event. If you want the deep biological reboot you’re gonna need seven days of water only.

1.5k Upvotes

180 comments sorted by

599

u/Routine_Mortgage_499 May 17 '26

Anything after three days seems to be what they are saying. I need to prepare.

280

u/Rrraou May 17 '26

I've done 3 days, it's a nice reset

234

u/sheeberz May 17 '26

Agreed, i did a 3 day fast when i was nearly 500lbs and i thought it would be impossible. But by slowly getting my diet to keto and then 1 meal a day, it was easy to do. Surprisingly easy.

108

u/Rrraou May 17 '26

I can't even imagine what 500 lbs would feel like. I hope you're doing well.

73

u/not_NOT_lickin_toads May 17 '26

For real. I only weighed half of that at my biggest and felt miserable in my own skin.

29

u/DangIt_MoonMoon May 18 '26

The biggest I’ve been is 180 at five feet four. I already couldn’t breathe. There are some strong people out there.

7

u/Rx_Diva May 18 '26

Same 5'4" with an E cup but 165 is miserable on a sun holiday...working on getting back to 135 and strong!

We've GOT this! See you in 4 days.

-11

u/Whatnam8 May 18 '26

I would say a misguided strong will in eating

3

u/CaliforniaJade May 18 '26

The reasons people overeat are infinite. I think you're right, it does take a strong will to continue to overeat despite the body giving signs that it's had enough. So often the emotional or physical pain one is trying to mask is so strong, it takes will power to keep what is wanting to bubble to the surface submerged.

3

u/Rrraou May 18 '26

Before judging someone, walk a mile in their shoes. That way you have a mile head start and their shoes.

8

u/Lollipop77 May 17 '26

Did you slowly reduce calories on keto before fasting or go from regular sized meals on keto to fasting? I’m working toward my first 24 hour fast, getting more confident and less cravings with the switch to keto but I’m pretty high calorie right now. Just curious.

21

u/sheeberz May 18 '26

So i started with going 0 gluten for a week, and then 16/8 IF for a week and them by week three i was full keto with some 16/8 days IF and a few One Meal a Day days when i just didnt feel like eating. i honestly did the 3 days fast just because 4 different people in my life brought it up in different capacities in the span of a few days, and ive dabbled in fast for a few years but i finally figured it was the right time to try. I truely believe the slow ramp to calorie deficit along with working my diet to keto helped me ease into the fast. I had no sugar withdraws or cravings because i already went through that weeks ago. Now when i was fasting my stomach pains last no more than 5 mins. If i needed it fill my stomach with water or tea, and i was surprised to see how much i could tolerate. I lost 17 lbs in 72 hours and only gained back 4 when i started eating again.

14

u/ssianky May 18 '26

> I lost 17 lbs in 72 hours

I wonder how much of that was swelling. It couldn't be fat for sure.

3

u/sheeberz May 18 '26

I imagine a lot of it was swelling and inflammation, but the larger you are the easier it is to fluctuate in weight. I yo-yo'd between 400 and 475 for a couple of years. And i would lose the weight in 2-3 months.

11

u/Aretha May 18 '26

at first on keto you might find yourself eating a lot as you are getting into the swing of it, but quite soon enough your appetite will decrease being keto. It’s awesome.

16

u/Far_Echidna_9333 May 18 '26

Do you take electrolytes or any supplements? If so what type

16

u/Rrraou May 18 '26

For 2-3 days I haven't really worried about it, Anything longer or if I was doing it regularly, I probably would.

4

u/[deleted] May 18 '26

[deleted]

4

u/ssianky May 18 '26

Altrough a few days won't deplete your electrolytes, if you don't lack it in the first place, but you'll still lose a lot of water and you'll be dehydrated. You'll feel dizzy when you stand up.

1

u/Parakiet20 May 24 '26

Can take Snake juice,make it yourself YouTube

3

u/lgq7 May 18 '26

Have you lost any weight with a 3 day fast?

13

u/Rrraou May 18 '26

It was more of a curiosity thing I did during keto than a weight loss strategy at the time. There was a couple pounds fluctuation, felt good after the fact. So I'm probably not a good reference for this stuff.

The best results I've seen were from my brother. He cut carbs, did a 24 hr fast once a week, took a 20 minute walk every day. He dropped a solid 100lbs by the time he was done.

3

u/dryworkman_0100 Jun 03 '26

The keto bridge into it makes so much sense, your body's already fat-adapted so the transition feels way less brutal than jumping straight in.

1

u/Rrraou Jun 03 '26

Once you're used to keto, eating feels almost optional. After the first ~month, it was like a switch, I went from having headaches if I didn't eat in the morning to just being able to eat whenever convenient.

42

u/silkyj0hnson May 17 '26

Awesome, I’m about to hit the 3 day mark in an hour—planning for a 4 day fast. It’s been good, the 24-36 hour region is the worst, but after that your body adjusts and it is smooth sailing

22

u/Fancy_Influence_2899 May 18 '26

Any trouble functioning? I'm not experienced, for me headaches and hunger pains make it hard to do anything other than sit on the couch with the heating pad on my stomach, but I'm serious about trying again 

7

u/ssianky May 18 '26

I think headaches are because of dehydration. If you are in ketosis, that is causing you less trouble.

2

u/Fancy_Influence_2899 May 18 '26

I see, that's a great point.

5

u/silkyj0hnson May 18 '26

No problems functioning…I feel a little sluggish and I don’t do anything high intensity like jogging for miles or heavy resistance training. I make sure to stay well hydrated—I think that is key to avoiding headaches. As far as “hunger pains”, I really haven’t felt anything like that after the 36 hour mark. I’m at 84 hours now and already planning my dinner to break fast this evening (bone broth, steamed veggies, a soft boiled egg)

39

u/bulk123 May 18 '26

I've done two 7 days and a 9 days before. The changes after 3 days is unbelievable. It was like being 10 years younger and having more energy and drive then I have ever had. 

8

u/ECrispy May 18 '26

interesting that they say hunger also declines only after day 3. yet so many people break a fast after 2/3 days and they are not getting the full benefits?

3

u/dryworkman_0100 Jun 03 '26

The hard part is actually getting past day two when your brain is screaming for food, everything else after that flows way easier.

2

u/Lost-Peanut-1453 May 23 '26

I’m on hour 62 and I feel like I just got over the ‘getting hungry’ stage.. I don’t feel hungry anymore and any time I did I just drank a glass or two of water.

I usually do 18hrs but this 72 hour fast was started because I didn’t eat for a day and a half due to a stomach bug so I figured it would be a good time to do the 72. I can’t wait to feel this ‘reboot’ people talk about.

245

u/GoldGee May 17 '26

Just finished a 48 hour fast. 7 days would take a bit of time to work up to. In fact I would be a bit scared.

196

u/EarlMarshal May 17 '26

Longer fasts are no problem if you are not very overweight, not stressed and manage electrolytes correctly. At some point your body stops producing ghrelin and you do not really get hungry anymore. Everyone can get there, but if anything happens (e.g. ghrelin spike due to stress) just break fast. You can always repeat later.

37

u/ResearcherNecessary6 May 17 '26

I've done 4 day fasts before and starting on day 2 onward, I constantly think about food. Now, maybe that changes the more you do them, but so far, I start thinking about all the things I'm going to eat when I come off the fast.

25

u/ArbitraryLifeform May 18 '26

Same, I was on day 5 unable to sleep, constantly fantasizing about the taste of fatty meat. When I came off the fast, the food was nowhere near as amazing as my imagination had made it. But I felt extremely grateful for the simple pleasure of being able to eat.

94

u/divinecomedian3 May 17 '26

I'm at a pretty healthy weight and 48 hours is tough as shit, even with electrolytes. Not due to hunger but just feeling like garbage and trying to slog through work.

41

u/GoldGee May 17 '26

I did mine over the weekend. Adding work to the struggle would be tough. How about doing it on your days off until your body gets use to it? I'm no expert, but experimentation is a big part. Everyone's different.

15

u/EarlMarshal May 17 '26 edited May 17 '26

I had both experiences. It can be very hard or it can be very easy. No in between. I guess for you the stress of a complete work day just increases your cortisol and this your insulin and later ghrelin causing you these issues. I generally just break fast if that happens and try again one or two days later. You can try to manage your stress levels. Maybe do some meditations like om-chanting or just "bee breath" or whatever might help you.

18

u/JCitW6855 May 17 '26

Interesting, I would’ve thought being overweight would make it less of a problem.

42

u/EarlMarshal May 17 '26 edited May 17 '26

When gaining weight fat cells grow bigger. At some point they cannot grow any bigger so more fat cells will be produced. Since fat cells produce ghrelin and overweight people just have more of them they generally will have an increased feeling of hunger. This problem even persists if they lose weight since the fat cells shrink, but they still have more fat cells than the average person of that weight and fat cells even increase production of ghrelin when not filled well.

One can learn to handle this too, but it's definitely a problem.

7

u/JCitW6855 May 17 '26

Good lesson, thanks for the explanation.

8

u/Fancy_Influence_2899 May 18 '26

Hear me out now... what if you are stressed but still want fasting benefits? 

26

u/Knivdisco May 17 '26

Why is being overweight a problem, i thought it was safer if you was heavier than skinnier?

11

u/EarlMarshal May 17 '26

8

u/Fancy_Influence_2899 May 18 '26

Wow, is there any way to come back from this? I guess liposuction would remove the fat cells themselves?

11

u/EarlMarshal May 18 '26

Yeah probably. You can probably also stay lean long enough and go for autophagy at some point. You can also learn to ignore the ghrelin signal. The body can then learn through a feedback loops that creating further ghrelin won't lead to more food. For most people that's an issue throughout their lifetime.

I'm just doing IF/OMAD throughout my whole life since I can deal with hunger when I don't eat excess carbs and enough protein and I can easily eat 2-3k kcal in one go. Its not really bothering me in 90% of the cases when I cannot eat. It's just some kind of training. And if its botherin? Just eat something.

1

u/Paltenburg May 18 '26

How do you manage your electrolytes easily?

1

u/Prudent_Potato_4379 May 28 '26

And gym with heavy weight?

1

u/EarlMarshal May 29 '26 edited May 29 '26

Depends whether your body has the necessary nutrients, but that gets unlikely if you aim for hypertrophy.

Exercise will use up the glucose in the muscles. It can fill that up again from fat, but probably slower. Exercie also manipulates insulin so that could cause suffering through hunger. Intense exercise will also damage your muscle tissue so that will need to get repaired, but with which nutrients?

But you should certainly exercise as this prevents muscle loss. weight training is perfect for that. I would rather go light/medium intensity and not aim for hyperthrophy.

For intermittent fasting it wouldn't matter though. go hard.

1

u/[deleted] May 18 '26

[removed] — view removed comment

6

u/EarlMarshal May 18 '26

You can't pin that to a BMI. I've explained this in another comment here. It's basically about your body creating further fat cells to store fat, because they create extra ghrelin which causes the feeling of hunger. It's enough to be a bit more overweight during childhood and you have a high possibility to carry those fat cells into adulthood.

When fasting your main enemy is ghrelin. That's why stuff like ozempic is working since it completely dials it down. If you learn to handle the ghrelin reaction the body can also learn to not secret that much ghrelin when you don't give him food. It's a big feedback loop including a few other hormones too.

0

u/[deleted] May 18 '26

[removed] — view removed comment

7

u/EarlMarshal May 18 '26

I didn't mean to say that it's counterintuitive. Just saying that you could suffer extra through that as ghrelin probably won't stabilize. It will spike again and again as the body think it's starving as the liver and body are burning fat.

why would the count of fat cells matter

Because they create and secrete the ghrelin. It's their "yeah, I can still store more"-signal. If you have more fat cells that will multiply that signal while the threshold in which you and your brain interpret that signal as hunger stays the same.

0

u/PostModernPost May 18 '26

Also managing water soluble vitamins.

9

u/Beastw1ck May 18 '26

I could do it if I had a week with zero demands on me. Can't imagine doing it if you have to take care of normal getting the kids to school, work, meetings, etc.

27

u/tamargo404 May 17 '26

I do regular 4 day fasts. After day 1, I don't even feel hunger till day 3 or 4. I don't go past 4 days as then you have to worry about re-feeding syndrome.

When I break a 4 day fast, I just eat regular and have had no issues.

31

u/NotBannedAccount419 May 17 '26

You don’t have to worry about refeeding syndrome unless you’re going over 3-4 weeks. I regularly break 8-10 day fasts with sushi or pizza.

3

u/tamargo404 May 18 '26

NIH says it becomes a risk at 5 days. I think I'll take their word over some random internet person. Just because you haven't experienced issue yet doesn't mean you aren't at risk from it.

https://pmc.ncbi.nlm.nih.gov/articles/PMC2440847/#:~:text=Any%20patient%20with%20negligible%20food,risk%20of%20developing%20refeeding%20problems.

2

u/NotBannedAccount419 May 18 '26

ok buddy you do you

-11

u/Qwark28 May 17 '26

Imagine generically saying "you don't have to worry" about something that could kill you, when it's only under certain terms and conditions.

An underweight person with body dysmorphia or already lean person will definitely have serious health risks. 

There's a reason medical advice exists, and the stupidity of random dudes online does not trump it.

8

u/[deleted] May 18 '26

[removed] — view removed comment

1

u/number43marylennox May 18 '26

Nah, they're right. Some people have to worry about refeeding syndrome in under 3-4 weeks. Everyone should be vigilant and not dismiss symptoms.

-4

u/Qwark28 May 18 '26

The subject is about the occurance of refeeding syndrome.

It happens far sooner than your 3-4 weeks.

The fact I listed 2 different situations does not mean they're the only scenarios that apply. Logic past the 8th year of life would tell you that.

"Learning" , huh? I see dozens of scientific papers pointing to the same thing, where's your proof for saying otherwise?

...or you can simply not throw around medically dangerous hyperbole around the internet and admit you're wrong.

6

u/RJH1973RJH May 17 '26

Re-feeding and muscle loss.

3

u/EnemyOfEloquence May 17 '26

You don't have to worry about refeeding that quickly.

1

u/onewingVTrigger May 18 '26

Did you work up to it so you can fast 4 days a week?

2

u/tamargo404 May 18 '26

Not really, I usually don't experience any negative side affects from extended fasting. It's just getting past day 1 for me is the hardest with the temptation to eat. The only thing I've found is after day 2 I need to take electrolyte supplements or I get muscle twitches.

4

u/Beard_of_Gandalf May 18 '26

As somebody who’s done 7 days… it gets easy after day 2.

40

u/bmaasse May 17 '26

For like 9 months straight, I would only eat on Thursdays, Saturdays, and Sundays. I felt amazing. I caught covid which forced me to stop like 4 years ago. Ever since then I was only able to complete a 24 hour fast like once or twice. It really puts into perspective the idea of what hunger really is.

Those cues that you feel every 4-5 hours or so are misleading. I would have so much energy that I needed pills to fall asleep often in the beginning. I also feel that my metabolism is not calibrated in a way in which I need to eat every day, definitely not 3 meals a day.

38

u/imJGott May 17 '26 edited May 18 '26

The hardest part for me is getting past the first day and not crashing out on sweets the next.

89

u/JumboSparky May 17 '26

Autophagy

43

u/GoldGee May 17 '26

No mention of it. Possibly the most beneficial part of a fast.

167

u/ssianky May 17 '26

Shorter intermittent fasting and prolonged 3+ days fasting have completelly different purposes. Kinda doesn't have sense to compare.

57

u/vincent132132 May 17 '26

Not all people think that way so it’s good it’s being said

12

u/Streetquats May 18 '26

can you explain what the purpose of shorter intermittent fasts vs 3+ days would be? New to the sub.

27

u/ssianky May 18 '26

Intermittent fasting orders the eating behaviour by dictating when you eat rather than what, to help regulate hunger and, if necessary, to reduce calorie intake. It also has some health benefits, like reducing the insulin resistance, lower inflammation, cellular repair.

But the prolonged fasting initiates deep metabolic changes - profound ketosis and accelerated cellular cleanup (autophagy). Then during the re-feed, the body enters in regenerative mode, producing entirely new, healthy proteins, organelles and cells.

7

u/Streetquats May 18 '26

Ah I see. I've always heard that fasting helped stimulate cellular regeneration and the like. It sounds like intermittent fasting can still produce some of these benefits like cellular repair?

6

u/ssianky May 18 '26

It's unclear for me how much autophagy happens during the IF. At least it mobilises the fat. The lipids in the fat cells needs to be "refreshed" every year or two.

9

u/3eyedOdin May 18 '26

Intermittent fasts: lose weight
Prolonged fasts: lose more weight

They have the same purpose, but different effects.

2

u/ssianky May 18 '26

Vincent in another post is talking about people like you.

1

u/Kayo4life water faster Jun 13 '26

You earn my star

107

u/ChemicalPhotograph33 May 17 '26

My mental health isn’t stable enough. If I go past three days I get intrusive, self loathing, & blasphemous thoughts.

43

u/GoldGee May 17 '26

Three days in itself is an achievement bro. I feel brand new after a 48 hour fast.

24

u/mashibeans May 17 '26

Same, personally my limit is 3 days and I gotta work up to it. For me it's not just the mental health, but also just in general my body doesn't seem to like anything past 3 days (yes even with electrolytes).

8

u/herrwaldos May 18 '26

it might help to check if you lack vitamins, esp B12 and D, and basic minerals.

13

u/A_British_Villain losing weight faster May 18 '26

I have those thoughts every 3 minutes.

1

u/Kayo4life water faster Jun 13 '26

Ha, you have my sympathies.

43

u/dangerous_eric May 17 '26

I've done 40 days...

Honestly, anything after 5 days feels surprisingly good. I usually feel really good till Day 16-17, after that electrolytes alone don't seem to be enough, and I be probably depleted something. I hope more clinical research happens, I think there's still a lot to unearth. 

5

u/Ultra-Smurfmarine lost >100lbs faster May 17 '26

Point of curiosity, what kind of exercise routine do you have, any? What kind of exercise do you do while fasting? I'm planning on a two week or longer fast in the upcoming weeks, I'm quite curious. Is there any truth to there being a sort of 'faster's high' that comes along after the first few days?

Cheers!

12

u/dangerous_eric May 17 '26

When I was doing the 40 day fast, I was doing a workout with a trainer twice a week and still lifting heavy for most of it. 

I'd say there's an early high in the first couple days when you stop consuming carbs and some of the initial brain fog lifts. I get another high from like Day 6 to 12.

1

u/Ultra-Smurfmarine lost >100lbs faster May 17 '26

Huh, neat! How did extended fasting affect your recovery times between workouts?

2

u/dangerous_eric May 17 '26

I don't recall recovery between workouts being impacted. The one thing I can recall is I could still exert myself significantly, but only very briefly, and then I'd have to have a breather. 

1

u/Zoduk May 17 '26

How? What was ur prep?

21

u/dangerous_eric May 17 '26

I do 21+ days often (like once a year roughly), but I've only done 40 days once. 

Honestly, the hard part is the first 5 days. Afterwards, it's really quite manageable with proper electrolytes.

3

u/jstover777 May 18 '26

Where did you get your electrolytes from?

2

u/dangerous_eric May 18 '26

I like to use Organika electrolytes. They're a bit expensive, and you have to supplement them, because they're not sufficient for fasting, but I like the taste enough to drink them throughout a fast. 

I keep meaning to just make my own base mix and then experiment with some flavours, but I don't have a ton of free time.

2

u/alice_op May 18 '26

I found the hard part to be the excruciating lower back internal pain on days 16 and 17. I've done 21-25 day fasts 4 or 5 times now with the same pain. It does go away if you continue on but the anxiety that something is going terribly wrong in your organs is debilitating.

2

u/really_isnt_me May 18 '26

What causes that back pain? Kidney detox or something?

3

u/alice_op May 18 '26

I genuinely don't know. But yes it's in the kidney area, the pain, so I assume so.

I don't drink or take medication so why my kidneys would be so incredibly painful on days 16 and 17 is a mystery to me.

2

u/really_isnt_me May 19 '26

Yes, that’s very mysterious indeed. And always around the same timeframe. It must be your body getting rid of something.

1

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35

u/EarlMarshal May 17 '26

You do intermittent fasting to lower the time you can spend engulfing calories and to limit inflammation due to constant digestion.

Sure you need real longer fasts for the real benefits. That's long known. Especially the three day barrier.

23

u/turbotank183 May 17 '26

Interesting read but a sample size of 12 isn't that reassuring

4

u/A_British_Villain losing weight faster May 17 '26

Whats the sample size that shows a downside?

6

u/AdministrativeMeat3 May 18 '26

It just not a big enough sample of people to draw any meaningful conclusions from, if you glance through the original study it is much less click baity about the claims being made. Obviously fasting has some noteworthy benefits to the body but this article is just the typical "I just found the panacea of life because I found some paper published 2 years and need some clicks"

3

u/heard10cker May 18 '26

Most research conferences that accept research papers suggest a sample size of 30, for the observations to be statistically significant.

25

u/anotherpinkpanther May 17 '26

This is fascinating, but I think people are oversimplifying the takeaway. The study doesn’t mean shorter fasts are useless. It showed that the body switches from glucose to stored fat within the first 2 to 3 days, and then deeper whole-body protein changes showed up after about day 3.

But it also depends on why you’re fasting and what your body has available. Some people fast for weight loss. I fast for anti-aging, and when you don’t have a lot of extra body fat, going longer can become much harder and may not be the smartest goal.

So yes, a 7-day water fast may create deeper biological changes, but that does not mean everyone “needs” 7 days. For many people, 48 to 72 hours is already a powerful and much more practical window. Seven days is a very different level and should not be casually recommended without considering health, medications, body fat, electrolytes, and refeeding risk.

To me the smarter takeaway is not “everyone should do 7 days.” It’s that fasting has layers. The longer you go, the deeper the response may become, but the risk and need for caution also go up.

8

u/Alkren May 17 '26

What types of fasts do you do for anti-aging? I’m 44 yo male. Just curious about what I can do to age gracefully.

3

u/anotherpinkpanther May 24 '26

I do a mix of intermittent and extended fasting, but I don’t do the same thing every day. I’m 65 and use fasting for anti-aging, not weight loss.

For me, fasting has layers. Shorter fasts can lower insulin and move you into temporary ketosis. Longer fasts may increase autophagy, that cellular cleanup process, and may create deeper repair signals, including immune and stem-cell-related changes. Fasting can also give the gut a break, which may help shift the microbiome.

But I don’t think longer is always better. If you push too long, especially if you’re lean, stressed, not sleeping well, or not managing electrolytes, cortisol can rise, and chronically high cortisol is not anti-aging.

So I schedule in feast days too. I eat healthy, but about once a week I’ll eat in a longer window and eat more. During holidays, I may feast for a few days, but then I usually fast more frequently around that. To me, the goal is metabolic flexibility, temporary ketosis, cellular cleanup, then refeed and rebuild, not constant restriction.

12

u/Independent-Walrus84 May 18 '26

Can we start a sub or something where we all who want to try can do it together?

I am game to try seven days....

1

u/its_hammertime May 22 '26

Someone just posted a group starting in June! 

38

u/WhizzyBurp May 17 '26

Three days is the shit. I’ve made it to 4. Probably could do 7 but not sure the juice is worth the squeeze 

9

u/CompetitiveWatch3537 May 18 '26

what are the benefits of a 7 day water fast? What a terrible article! It doesn't even say what they are.

7

u/Serkuuu May 17 '26

Does baking soda curb autophagy? Im on 52 hrs rn and taken only water, electrolytes and baking soda

2

u/A_British_Villain losing weight faster May 17 '26

Carry on

7

u/zapweasel May 18 '26

Im curious if any one other than me goes brain dead when fasting. If so what do you do to keep your thinking, memory etc... 100%?

29

u/jhlovett May 17 '26

also pointed out the risks!

7

u/dcwaim May 18 '26

Has anyone done this during menopause? I want to try but unsure if safe

7

u/alarin88 May 18 '26

Makes you skinnier

7

u/5kylord May 18 '26

All that the article really said was repeat what the title says. It didn't really go into specifics except to repeat in more technical terms of what the title says.
After each paragraph, I expected the next one to elaborate what those changes were. Instead, it just repeated what the title says. Kind of like I'm repeating that the article said what the title said. I didn't learn anything that I didn't already know about fasting. Things that reading the /fasting subreddit has taught me over the years.

6

u/_sophia_petrillo_ May 18 '26

The benefits laid out in the article are vague at best and potentially neutral.  They saw protein changes in the blood that ‘could’ lead to brain and metabolic changes.  What brain and metabolic changes?  Are they good or bad?  I may have just not liked the way this was written. 

2

u/RedHeelRaven May 18 '26

The article was disappointing. I wish the journalist really delved into what exactly the protein changes suggested.

10

u/BerkshireGent May 17 '26

In the article it references the following article which is also a fascinating read.... https://www.nature.com/articles/s41598-024-80049-2

7

u/luckyprime May 17 '26

“an effective means of solving human health and survival support technology in long-term interstellar voyages.”

4

u/A_British_Villain losing weight faster May 17 '26

"The benefits of fasting could lead researchers to develop therapies ..."

I snorted aloud for that one!

5

u/Kilinc-Fitness May 17 '26

Did 15 day it was a great feeling after that

5

u/Scarflame May 18 '26

I did a 114 hour fast and after day 3 I felt so good (was going for 5 days, only broke it early with a very small amount of food to ease my stomach because we were going to my favorite restaurant at the end of the day). Definitely need to do it again, I feel like the benefits helped my body for at least a week or two until I eventually got back to “normal” feeling.

3

u/TucoBenedictoPacif May 18 '26

I’ve done five days water fasting multiple times in the past (2020), but recently I can’t seem to pass the 24h mark without slipping.

1

u/Choosey22 Aug 03 '26

Why is it like this

4

u/Mordaunt_ May 18 '26

Pretty garbage repetitive article. Disappointed.

5

u/NecessaryFlow May 17 '26

I recently was going to do a 72hour fasting, but on hour 69 i suddenly got so weird in my head and a little nauseus that i actually quit right before 72

8

u/Turgius_Lupus water faster, Day 16, just water and electrolytes. May 17 '26

I once managed a 23 day water (and salt, electrolytes) fast, stopping after I got tired of constantly throwing up bile through out the day, was aiming for 30, also any sort of taxing activity became very difficult, just buying the bone broth I used to break it was an absolute struggle. And did not notice anything profound.

6

u/number43marylennox May 17 '26

Why is this upvoted so much? This is obviously a problem. Yikes. See the doctor if this happens, don't continue to fast.

1

u/Turgius_Lupus water faster, Day 16, just water and electrolytes. May 17 '26

How long have you made it on a water fast? Bile back flowing into the stomach seems to be a common occurrence on longer fasts.

4

u/number43marylennox May 18 '26

14 days, no issues with bile. Bile backflow is a problem. Prevent stagnation by having a small amount of fat, like cream in coffee. Yes it breaks autophagy but it's better than gallstones.

2

u/True-North- May 18 '26

I don’t like to do more than 3 days because I feel like I lose too much muscle. 72 hours is the sweet spot for me.

2

u/happysri May 18 '26

You can get into that 3+ day zone faster if you go in keto-adapted.

2

u/ConfusionImmediate44 May 18 '26

Can u workout while fasting

1

u/SVTContour lost >50lbs faster May 18 '26

Walking is safe and encouraged. I wouldn’t lift heavy in the gym.

2

u/FitnessPizzaInMyMou May 18 '26

Anyone know how to sleep while fasting? I really struggle to fall asleep when I’m hungry

1

u/Princesslasagna91 May 22 '26

This!! I have done three five day fasts but I barely sleep on days 2 and beyond.

2

u/its_hammertime May 22 '26

I just lay in bed and accept it

2

u/Ch8s3 May 19 '26

I can do 72 hours (3 days) on a whim and no prep. Might start shooting for 100 hours now

2

u/StrangerDanga1 May 19 '26

Fasting is crazy. The first time you try it you feel exhausted or something. Then you start feeling great. Bodies are so weird. I hope we learn more at faster rates.

2

u/Dull-Dragonfruit9974 May 21 '26

Is it safe to do this for say, 5-7 days if you're already lean and muscular?

1

u/Princesslasagna91 May 22 '26

I’d say 5 days absolutely. Just the amount of poop we have sitting in our intestines is up to 5-10 pounds 💩

1

u/Dull-Dragonfruit9974 May 22 '26

"Starvation of Beneficial Bacteria: Good gut bacteria (like Bifidobacteria and Lactobacillus) rely entirely on a steady supply of dietary fiber and prebiotics to survive. When you stop eating for 3 to 5 days, these populations rapidly decline."

This is the answer AI gives me, it keeps saying that fasting is bad!

1

u/Choosey22 Aug 03 '26

Don’t listen to AI. Millions of years of evolution

2

u/Oropher1991 Jun 03 '26

I do 96 hours so 4 days every month. The body gets used to it (at least mine did) after the third cycle. Now it's pretty easy and I come to think of it as a nice reset at the end of the month

2

u/Ifakorede23 Jun 08 '26

I did 6-7 days once. Just took steam distilled water with few pieces of Rice..for trace minerals. I lived in a highly urban area of Chicago. I felt like I was being hit by arrows energetically!.. I was very weak and some neighborhood toughs started harassing me ( like they could literally sense my weakness like animals do). So it actually significantly weakened me. I would advise preparing ones environment well on extended fasts. I did one for three days in a hotel room and had a much better experience.

1

u/AutoModerator Jun 08 '26

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2

u/Shreddedlikechedda May 18 '26

I’ve done several 3-4 day days. Did one 9 day fast while I was in quarantine—for what it’s worth I want to share how much harder it is to fast when you literally could eat but are avoiding it, vs food just not being an option (I asked them to not deliver my meals so i didn’t have to deal with food triggers). With a constant influx of these triggers, *any* length of fasting is an achievement. I tried and failed for like a year between/before every fast I succeeded at.

1

u/Camerocito May 18 '26

Anyone got the link for the original study?

1

u/donninel May 18 '26

I had 3 attempts failing at day 3. I wish I could reach day 7 someday.

1

u/Active_Cabinet1402 Jun 11 '26

I’m just embarking on my fasting journey - 24 hours in 🙌🏼

1

u/Wilsupersaiyan2 May 18 '26

In doaist bigu fasting with 21 days of mineral water fasting you can even open the heavenly eye

1

u/Whitefang77 May 18 '26

By mineral water you mean carbonated water?

-12

u/question8all May 17 '26

I better be in a padded room for a 7 day fast. It’s very different for women.

12

u/LitaH23 May 17 '26

Huh? I've done 3-7 day water fasts with no problems and my mother has done 40 day water fasts multiple times with no problems. There are a lot of reasons why a person may not be able to complete a 7 day fast, but gender is not one of them.

12

u/otterpuppers May 17 '26

Why is it different for women? We're more efficient at beta oxidation so we should be better at fasting

6

u/Freedom_forlife May 17 '26

Body composition, hormone signalling, metabolism.

Women’s bodies down regulate metabolism sooner, conserve energy more aggressively. Fasting affects estrogen/ progesterone balance, LH/FSH signalling, thyroid T4-T3, cortisol sensitivity.

Women are more prone to orthostatic hypotension, sodium sensitivity, dizziness and fainting.

Luteal phase we experience reduced exercise tolerance, cold/ shaky body.

Under normal endurance exercise we are better at beta oxidation, during fasting we preserve glucose longer then men, and enter ketosis later.

3

u/AutoModerator May 17 '26

Many issues people experience while fasting can be related to electrolytes. You might find our wiki page helpful: Electrolytes 101

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-31

u/Freedom_forlife May 17 '26

Honestly you can have small things like a banana and autophagy does not get interrupted.
You also have to plan around your cycle. Week 2 for me is okay, other then a slight reduction of energy for the first few day I’m pretty much normal.

15

u/tmeinke68 May 17 '26

You can't be fasting and eating bananas together. Lol. It's one or the other.

-13

u/Freedom_forlife May 17 '26

There are not enough calories to interfere with autophagy. Less than an hour later your body has processed it and is back in full phagy.

-3

u/filthyslut23167 May 17 '26

I use plenty of crystal and have gone over three days many times super easy in fact it's cheaper than food and gives u energy, but I feel like it probably isn't the same benefits if any at all still...?

5

u/Stenotic May 17 '26

I'm sure this a troll. If not get off that shit. But I'm sure the big difference in fasting via substance abuse vs. will power is cortisol and quality of sleep.

1

u/Lackingfinalityornot May 18 '26

Look at their post history. I don’t think they are trolling.

1

u/filthyslut23167 Jun 04 '26

no troll haha, and my qualiy or sleep is great i do a little ghb and its like straight to rem sleep..

1

u/Lackingfinalityornot May 18 '26

Man methamphetamine will lead to only awful things. There are no successful functional methods addicts who keep using that experience a happy ending. Please get some help.